Matlab Graph

I am a bit lost with a current problem. basically I am looking to produce a graph the shows a number of different results.

The problem that I have been set is that i have to work out how many stones would hit a the car behind if traveling at 30 mph. So i have to produce a graph that would show the projected "flight" of stones at differing angels.

Can someone help and give me some advice on how to produce a graph, though open to better suggestions.